package org.deeplearning4j.graph.data.impl;

import org.deeplearning4j.graph.api.Edge;
import org.deeplearning4j.graph.data.EdgeLineProcessor;

/**A simple line processor, for data in the format
 * 0<delim>1\n 3<delim>0\n etc. Order per line is nodeFrom -> nodeTo, in the case of directed edges
 * i.e., one edge per line without any additional edge information
 */
public class DelimitedEdgeLineProcessor implements EdgeLineProcessor<String> {
    private final String delimiter;
    private final String[] skipLinesStartingWith;
    private final boolean directed;

    public DelimitedEdgeLineProcessor(String delimiter, boolean directed){
        this(delimiter,directed,null);
    }

    public DelimitedEdgeLineProcessor(String delimiter, boolean directed, String... skipLinesStartingWith){
        this.delimiter = delimiter;
        this.skipLinesStartingWith = skipLinesStartingWith;
        this.directed = directed;
    }

    @Override
    public Edge<String> processLine(String line) {
        if(skipLinesStartingWith != null){
            for (String s : skipLinesStartingWith) {
                if (line.startsWith(s)) return null;
            }
        }

        String[] split = line.split(delimiter);
        if(split.length != 2) throw new IllegalArgumentException("Invalid line: expected format \"" + 0 + delimiter +
            1 + "\"; received \"" + line + "\"");

        int from = Integer.parseInt(split[0]);
        int to = Integer.parseInt(split[1]);
        String edgeName = from + (directed ? "->" : "--") + to;
        return new Edge<>(from,to,edgeName,directed);
    }
}
